Conventional systems for beautifying or otherwise treating various parts of the face, fingernails and toenails and other parts of the body, particularly the skin, rely on applying liquid, liquid based or solid, e.g. powder, products via regimes such as brushing or wiping, or alternatively direct application of the product which is in the form of a stick or pencil. These known systems are frequently location dependent, for example are restricted to use in the bedroom or bathroom, are messy, difficult to control, inconvenient and time consuming. As a particular example of this, the conventional application using a soft brush of solid powder colour cosmetic products such as blushers is particularly time consuming and it is difficult to achieve a particular desired level of colour application especially in regions where even colour fading is required.
Frequently, conventional colour cosmetic products utilise an oily carrier or vehicle base to enable the colour cosmetic to be applied at concentrations suitable for attainment of the desired cosmetic effect. Such oily carriers and other adjuncts contribute to the messiness of known application regimes and may be particularly troublesome to the user where make up for example is to be applied in various stages. These known systems also represent uneconomical use of cosmetic raw materials.
A further problem encountered with known colour cosmetic application techniques is that when such products are to be applied in multiple layers, such as when making up the face, the use of brushes, pads and other direct contact delivery means such as sticks or pencils, may often disrupt previously applied materials, so that considerable care, time and application control must be exercised if the desired cosmetic result is to be successfully achieved.
Such direct contact deposition means also suffer from the difficulty of achieving 100% coverage of any particular region of skin surface, owing to its uneven texture and surface profile, which results in inefficient use of colour cosmetic products and less than optimum attainment of desired colour cosmetic effects.
In a very different technical field, the principle of electrostatic spraying of liquid and solid materials is also known. In this technique a formulation to be sprayed is raised to a high electric potential in a spray nozzle to cause the formulation to atomise as a spray of electrically charged droplets. Such electrically charged droplets seek the closest earthed object to discharge their electric charge, and this can be arranged to be the desired spray target. Hitherto, electrostatic spraying techniques have been proposed principally for only large-scale industrial and agricultural applications, especially for delivering reactive materials like paints, adhesives and other surface coatings, as well as large-scale delivery of pesticides and other agricultural or agrochemical formulations. Examples of disclosures in this field include GB-A-1393333, GB-A-1569707, GB-A-2092025, EP-A-029301, EP-A-253539 and WO-A-85/00761, the contents of which disclosures are incorporated herein by reference. In the context particularly of electrostatic spraying of paints and other pigments, there may also be mentioned the following prior art references, the disclosures of which are also incorporated herein by reference: EP-A-234841, EP-A-195546, GB-A-1478853, GB-A-1464370, GB-A-1461385 and GB-A-1364244.
More recently, there have been a small number of proposals for utilising the known principle of electrostatic spraying for delivering particular materials in specific applications other than those mentioned above.
EP-A-224352 suggests the use of an electrostatic sprayer for delivering a pharmaceutically active agent to the eye, to replace conventional ocular treatment using eye drops.
JP-A-56-97214 (dating from 1981) suggests the use of electrostatic spraying for applying a granular (i.e. solid particles of) colouring material to hair to effect surface coating thereof. However, the disclosed system is unsuitable for small scale personal use and fails to present significant consumer applicability and appeal.
One tentative proposal for applying the principle of electrostatic delivery to the deposition of fingernail colouring materials is disclosed in FR-A-2415439, which dates from January 1978. The author of that reference suggests electrostatic projection as a means of depositing small coloured synthetic fibres to fingernails which have been pretreated with an adhesive varnish. However, this early reference contains no suggestion of how the fibres may actually be delivered to the desired target and moreover the disclosed system has little practical usefulness or consumer applicability and appeal.